More elegant way to achieve the same + fixed KT-7746 Top level package name completion does not work inside class body

#KT-7746 Fixed

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/BasicCompletionSession.kt

@@ -233,11 +233,11 @@ class BasicCompletionSession(configuration: CompletionSessionConfiguration,
     private companion object {
         object NonAnnotationClassifierExclude : DescriptorKindExclude {
             override fun matches(descriptor: DeclarationDescriptor): Boolean {
-                return if (descriptor is ClassDescriptor)
-                    descriptor.getKind() != ClassKind.ANNOTATION_CLASS
-                else
-                    descriptor !is ClassifierDescriptor
+                if (descriptor !is ClassifierDescriptor) return false
+                return descriptor !is ClassDescriptor || descriptor.getKind() != ClassKind.ANNOTATION_CLASS
             }
+
+            override val fullyExcludedDescriptorKinds: Int get() = 0
         }
 
         val ANNOTATION_TYPES_FILTER = DescriptorKindFilter(DescriptorKindFilter.NON_SINGLETON_CLASSIFIERS_MASK or DescriptorKindFilter.PACKAGES_MASK) exclude NonAnnotationClassifierExclude

idea/idea-completion/testData/basic/common/TopLevelPackageInClassBody.kt

@@ -0,0 +1,5 @@
+class A {
+    kot<caret>
+}
+
+// EXIST: "kotlin"

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -865,6 +865,12 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
             doTest(fileName);
         }
 
+        @TestMetadata("TopLevelPackageInClassBody.kt")
+        public void testTopLevelPackageInClassBody() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/TopLevelPackageInClassBody.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("TypeParameterFromOuterClass.kt")
         public void testTypeParameterFromOuterClass() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/TypeParameterFromOuterClass.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -865,6 +865,12 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
             doTest(fileName);
         }
 
+        @TestMetadata("TopLevelPackageInClassBody.kt")
+        public void testTopLevelPackageInClassBody() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/TopLevelPackageInClassBody.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("TypeParameterFromOuterClass.kt")
         public void testTypeParameterFromOuterClass() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/TypeParameterFromOuterClass.kt");